Internal-combustion engine.



M. W. HALL. INTERNAL coNlBusloN ENGINE.

APPLICATION FILED AUG. 1 1. 1917.

Patented Nov. 5, 1918.

@be/M By Attorneys, l 'aouf. JW* MW IVI. W. HALL.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED AUGI|. IgI?. 1,28%, 1.99. Patented Nov.

3 SHEETS-SHEET 2.

INVENTOR By l A torncys, 'Amcm @Mh f ITNESSES M. w. HALL.|NTERNAL`COMBUSTION ENGINE.

APPLICATION FILED AUG-I1. IBI?.

Patented Nov. 5, 1918.

3 SHEETS-SHEET 3- R O T N E V m By Attorneys,

WlTNEssEs f MILAN W. HALL, OF NEW YORK, N. Y.. ASSIGNOR, BY MESNEASSIGNMENTS, TO PISTON- VALVE MOTOR COMPANY, A CORPORATION 0F DELAWARE.

iesaiee.

Application led August 11, 1917.

To all 'whom t may concern.'

4Be it known that I, MILAN W. HALL, a citizen of t-he United States ofAmerica, residing in the borough of Manhattan, city, county, and Stateof New York, have invented certain new and useful Improvements inInternal-'Combustion Engines, of which the following isa specification.

This invention relates to internal combustion engines for combustible orexplosive gas or vapor. of the four-cycle type.

The objects of the invention are the production of a motor with apositively actuated and reliable valve-mechanism, adapted* for highspeed, and for the attaining of high elliciency.

The invention is characterized by the construction of the inlet andexhaust valves as pistons working the one within the other and receivingthe pressure of the expanding gases, under such conditions that asensible proportion of the total power of the motor is developed againstthese piston valves. The valves are connected to aivalve crank shaft.which is suitably geared to the main crank shaft so as to turn at halfthe speed ot' the latter, as is typical of four-cycle motors. rlhus thevalves, instead of being moved by power taken from the main crank shaft.are impelled forcibly by the explosions and become power-generatingmembers ot the engine. ln a suitable embodiment of the invention as muchas twenty per cent. of the total power of the motor is developed by theexpansion of the burning gases against these piston valves.

rlhe invention iiords a means of operating under high compression, insuch manner as to attain the greatest expansion, and also of avoidingexcessive cooling loss. resulting in important economy of fuel. Itv alsoprovides means for regulating the compression at will, so that itmay loebrought to the closest practical approach to the point of pre-ignition.The preferred embodiment of the invention is shown in the accompanyingdrawin frs. wherein,-

Figure 1 is a vertical transverse section;

Fig, 2 'is a vertical longitudinal mid-section;

Figs. 3 to 8 inclusive. are fragmentary diagrammatic views. being halfsections Specification of Letters Patent.

rammed New. 5, isis. Serial No. 185,680.

through the valvesraiid valve ports, and illustrating successivepositions in the cycle'of the engine;

Fig. 9 is a diagram showing the crank path of the main crank shaft, andthe points of opening and closing of the respective valves;

Fig. l0 is a' fragmentary section taken approximately in the planes ofthe line 1010 in Fig. 2, showing means for regulating the compression iFig. 11 is a plan of the exhaust valve, pai'- tially in section, showingthe construction of the pitman connections therewith; y

F ig. 12 is-a section through the crank shaft bearing.

Thev drawings illustrate a single cylinder engine, but it is to beunderstood that the invention may be applied to engines having any ofthe customary number of cylinders, as, for example, two, three, four,six, eight, twelve. etc.

In the drawings, A is the engine cylinder. shown as made up of ajacketed casting (i and lining 6,' B is the piston or plunger, connectedby the usual pitman C with the crank ai on the crank shaft D. Thepit-man connects with the plunger by means of a wrist pin c which forlightness is shown being tubular. rThe cylinder is extended upwardlyconsiderably above the top stroke of the plunger, and within thisextended portion. which is iacketed and has a lining f, slides aplunger-shaped piston valve E which constitutes the exhaust valve. This,valve is formed annularly, having an inner cylindrical portion F withinwhich moves a plunger-shaped piston valve I constituting the inletvalve. rllhe exhaust valve E and inlet valve I are connected to cranksor eccentrics on the valve shaft G by means of pitnien H and Jrespectively. To balance the construction there are two pitnien Hengaging twin eccentrics i 71 and between them one pitman J engaging asingle eccentric '7'. These eccentrics are shown as having equal throw,although this is not essential. ln the diagrams Figs. 3-8, only theeccentric centers are shown, the circle a' indicating the path of thesecenters. Of course. cranks may be used instead of eccentries.

'The inlet conduit z' or in a multi-cylinder engine the inlet manifold)is extended horis a communicating exhaust zontally along one side of theengine, and the exhaust conduit c (or manifold) is extend ed along theopposite side. These inlet and exhaust conduits are provided with waterjackets g g. From the inlet conduit z' there leads an inlet passager15extending through the cylinder Jacket a and communicating with anannular cavity 16 between this jacket and the lining f, and thence witha prolonged ort opening 17 in this lining, whence the in owing mixturepasses by a port 18 in the outer side of the exhaust valve E into anannular chamber 19 in said valve, and thence by an inlet port 20, whenthis port is uncovered by the inlet valve l, (see Fig. 6) into thecylinder.

rlhe exhaust conduit e communicates with the cylinder through an exhaustport 21 which is best extended annularly around the cylinder through itslining f and co-inciding groove in the jacketed casting, and throughpassage 22.

rlhe valve pistons E and l are best provided with packing rings 23 and24: respectively, to make tight joints with the cylindrical linings.through which are Jformed the ports 20 and 21 respectively. Y

It will be understood that the valves E and l are essentiallyreciprocally-acting slide-valves which for convenience and symmetry aredeveloped annularly into cylindrical form. The reciprocal operation ofthesevalves with respect to the plunger may l which corresponds torespond to the crank positions l crank path now be followed, it 'beingunderstood that the valve shaft Gr is inany manner connected to thecrank shaft D so as to revolve at half the speed ofthe latter, as istypical with tour-cycle motors.

The diagrams Figs. 3 to 8 inclusive, show the positions of thevalves atthose positions of the power piston or plunger which corshown in Fig. 9.In Fig. 9 the crank positions corresponding tothe valve positions of thepreceding diagrams are numbers thereof. In Fig. 9 the circle y indicatesthe crank'path; and in Figs. 3-'8 the dotted circle y indicates aportion of this (but of smaller radius) superposed around the circle mto show on each figure the angular position of the crank the valvepositions shown.

Let us start on the assumption that the explosive mixture has been drawnin and compressed, and is at the point of ignition. This is thecondition shown in Fig. 8, and in Fig. 3 the dotted lines 25, 26 showrespectively the lower position of the Valves and the upper position ofthe plunger at the point of ignition. During the power stroke theplunger B descends to the crank posiltion 3 in Fig. 9, at which pointthe exhaust A .valve begms to open,

this being the position shown in Fig. 3. During this effective `fullopen position Aconduit through indicated by the gure let, ports into theinlet conduit of the inlet valve, that is to say,

Apoint 7 to the top of its asettico power stroke the respective valvesare moved up from dicated by the dotted line 25 to those indi cated bythe full lines in Fig. 3. 1n so moving they are impelled by the pressureof the burnin gases and communicate power through their pitmen H and Jto the crank or eccentric centers, whereby a certain fraction of thepower generated by the engine is communicated to the valve shaft.

l/Vhile the crank shaft is turning from positions 3 to 4 (Fig. 9) thevalves aremoving from the positions shown in Fig. 3 to those shown inFig. 4. During this movement the exhaust valve is opening and theexhaust or scavenging operation is inaugurated. rllhis exhaust iscontinued during the remaining ascent of the plunger, during which timet e exhaust is closing, this closure being completed at approximatelythe top stroke of the plunger` or preferably shortly thereafter, asindicated by crank position 5 in Fig.y 9, at which point the valves arein the positions shown in Fig. 5, the exhaust having just closed and theinlet being about to open. The opening of the inlet which thereuponensues, is eiected mainly by the downward movement of the exhaust valve,which carries the port 20 down beneath the bottom l.; as this movementcontinues the valve I moves down, although more slowly, until the of theinlet shown in Fig. 6 is attained, at which time the main crank is inposition 6, Fig. 9. During the descent of the plunger from position 5,through position 6, to its bottom stroke, the explosive mixture is beingdrawn in from the inlet ports 113-20. These ports remain partially openduring a portion ot' the up stroke of the plunger and While the inletvalve is closing; that is to say, until time the crank has reached thepoint 7 in Fig. 9. During this portion of the up-stroke of the plungerits effect is to expel a portion of the mixture previously drawn in byforcing it back through the in- The et'- fect of this partial expulsionof the charge ris both to insure a more exactly measured charge ofmixture at all speeds, and to delay the period of compression. Whilesome compression commences toward the closing of the position 7, themajor compression takes place during the ascent of the-plunger fromstroke indicated by crank position 8 in Fig. 9, which is the position ofignition, being that shownin Fig. 8. Thereupon the compressed charge isignited and the operation just described is repeated.

A study of the valve movements during this cycle indicates that duringthe intake or suction stroke both valves are descending, s0

of the inlet valve in advance.Y

llU

that lthe suction is due wholly to the descent of the plunger. Duringthe period 'of expulsion of excessJmixture the valve E 'is nearlystationary and the valve I is descending, so that the latter valvecontributes to the expulsion. During the period of compression'(positions 7 to 8) the valve E is the most eiicient propeller speedis'about vversely, the

rising andthe valve I is descending.v Toward the close of thecompression the packing rings 24 are passed beneath the inlet ports 20(see Fig. 8) so as to make a tight joint and prevent leakage of thecompressed mixture back through theinlet ports; and this conditioncontinues during the entire power stroke, c'. e., from the positions ofFig. 8`to those'of Fig. 3.

The displacement of the valve piston during the effective portion of thepower stroke may be seen by comparing the dotted line 25 with the fulllines indicating the bottoms `of the valves in |Fig. 3. During thisdisplacement the valves become power pistons which are being forced upby the pressure,

and 'power is thus, delivered to the valvey shaft. The .power thustransmitted through the valve pistons is in proportion to theirdisplacementl as compared with the coincident displacement of theplunger. As the are geared'posishown in Fig. 2 as' projecting outthrough the inclosing casing of the engine.

- l The feature .last referred to is of advan-` tage for certain useswhere it is desirable to avail of two different speeds generated by theengine. Thus, for example, in aviation work, where it has been foundthat 1,200 revolutions per minute, the propeller may be driven fromthevalve shaft at that speed whilel the bulk of the power is developedat the main crankshaft at a speed of.

2,400 Rc1?. M., whereby the weight of the motor per horse power isgreatly diminished as compared with an engine the crank shaft of whichturns at the preferable speed for the propeller. AW'ith an engine oftheproportions shown in the drawings, the division of powergeneratedbetween the crank shaft and valve shaftis. approximately as 4 to 1; or,inother words, the valve shaft generates about twenty per cent. of thepower. These' proportions may, of course, be greatly varled.

.taken from the crank shaft, and ,which themselves have no part in theeffective generation of p'ower,-the new construction renders the valvesand valve shaft an appreci-A able part of the `power-generating unit.Thus, frictional losses are avoided and the efficiency of the engine isincreased. The engine embodies also a degree of simplicityheretoforeiunattained in four-cycle motors. The construction ofgas-impelled valve. mechanism thus provided by this invention enablesmuch higher speed to be maintained than is possible with motors ofconventional design; in fact, its speed possibilities are limited onlyby perfection of design, material, workmanship, lubrication, dynamicbalancing, andother minor details.

Another feature .in which this invention has important advantagesv is inthe securing of an -unusual degree'of fuel economy.. To this end itavoids in an important degree the Adeficiencies of ordinaryinternalcombustion engines as respects compression,

expansion, and cooling loss. Compression as a rule being maintained inexisting engines at a point only about half of that it results thatanexpansion of` only three to four volumes can be attained. Excessivecooling loss being a .concomitant of low compression and limited.'expansion ratio, contributes to a loweconomy.

' .In the improved engine these defects have been practicallyeliminated. Tothis end the 'motor is l designed to operatef normally atthe highest possible compression permissible with a pre-mixed charge offuel and air,

means' being provided to maintain the compression at a point just belowthat of preignition.` The timing of the inlet valve whereby it remainsopen after the suction strokeand enables a portion of the indrawnmixture to be re-expelled, results in the measuring of a correct volumeof the mixture,- so that after compression and at the moment ofexplosion, the compressed'mixture bears the correct ratio to the volumeof the expansionstroke of the motorA (consldering both the main plungerand the valve pistons), whereby a much greater ratio of expansion isavailable than with engines as heretofore constructed. 'i

The reduction of cooling loss is accomplished principally bythediminution in the volume of the required. combustion space within thecylinder, together with such concentraton, of this space that the leastpossible external wall surface is presented to the cooling medium. Theengine hasno fixed cylinder head with its stead, the valveA pistons E Ioccupy the which is possible,

cooling jacket. In-

place "of a cylinder head and these pistons compression,

piston. This has the double effect of cooling the valve pistons and ofheating the incoming mixture.

The combined economies thus effected by operating the motor normally atmaximum and utilizing the greatest available expansion and reducing theloss in cool-ing, result in a reduction offuel consumed of from fty tosixty per cent.

Maximum compression is practically at-\ tainable only by compressing asclosely as possible to the point of self-ignition of the charge, andthis can be attained in practice only by providing means for controlling(either at will or automatically) the compression so as to keep it justbelow such point. To accomplish this some means for varying the extentof compression during the running of the englne is requisite. As thecompression is determined by the portion of the compression stroke ofthe plunger intervening between the closure of the inlet valve and thecompletion bf the plunger stroke at the igniting point, a convenientmeans of varying the compression is available by changing Vvthe valvetiming so as to corresponding to provided for taking up be able torelatively to the crank shaft while the engine is ruiming, so that suchtiming as will best aord the desired compression may be availed of underany existing running conditions. This result may be accomplished invarious ways, but most conveniently by varying the running relation ofthe valve shaft G to the crank shaft D so as to give the valve shaftmore or less lead or lag, as the case may be, relatively to the crankshaft. A convenient means of accomplishing this result which has severalpractical advantages over other mechanical expedients that might readilybe resorted to, will now be describedJ The connection betweenvthe shaftsD and G, shown in the drawings, is by means of a so-called silent chainK running on sprocket wheels L and M having vteeth in the proportion of1 to 2 and fixed respectively on the shafts D and G. Such a chain asordinarily applied would hold the shafts in an invariably rotativerelation. But with the supplemental means best shown in Fig. 10, thisrelation may be varied so as to bring about the desired retardation orlag of the valve shaft relatively to the crank shaft. For this purposethe chain is given a slack the extent of rotative displacement desired(which may be as much as 15 for the va ve shaft, corresponding to 30 forthe crank shaft), and a device 'in the nature of a double b lt tighteneris this slack on either one side or the other of the chain. This lead orlag the inlet valve closurel VVapart by aspring T which is compressedbetween projecting lugs formed on the arms so as to provide for a slightyielding of the pulleys R R suiiicient to take up the slack effectively,the spring having sufiicient stress to keep the chain tight during thenormally maximum pull or transmission of energy between the shafts. Twoscrews U U are provided, which are adjustable with respect to the leverarms, and the ends of which may strike together and form an absolutestop in the case of an abnormal'pull on the chain. For adjusting thestress of the spring one end thereof rests against a nut T which may bescrewed in or out on one of the screws U U in order-,thereby to more orless compress the spring. The lever P 'may be set in any angularposition by means of a set nut or clamp V engaging an arc-shaped slot ina fixed bracket AV so as to hold the lever P inany adjustment.

Let us assume that the relative positions shown in full lines in Fi 10are such as to cause the opening an `closing of the valves to thevarying positions indicated on the diagram Fig. 9, and in correspondingpositions shown in the diagrams Figs. 3 to 8 inclusive; and that thesepositions correspond Vto the maximum compression which is practicable,that is to say, just below the point of pre-ignition. If then theoperator finds that pre-ignition is in orderito avoidvthis, to make suchadjustment as will retard the valve shaft. This is accomplished byreleasing the lever P and moving it over more or less toward the rightor dotted line position. This has the effect of letting off chain on theright and taking up chain' on the left, which, if done while the crankshaft is held stationary, would turn the valve shaft backward any numberof degrees up to the maximum (say 15). The operator should, in normalrunning 'so retard or lag the valve shaft to an extent only sufiicientto avoid liability to pre-ignition. Having found this point, he shouldclamp the lever P fast in its new position. Such retardation of thevalve shaft has the essential effect of retarding the point in the crank'shaft at which/the inlet valve closes, s'o that instead of closing inthe position 7 in Fig. 9, it may close in a higher position, as, forexample, that shown at 7a occurring, he has, v

in rig.V 9. This proiongs the i,

period of freev expulsion of the mixture and` retards the beginning ofthe compression and consequently cuts down the portion of the strokeduring which compression-can occur, so that compression is reduced.

The described construction also is capable of imparting to the enginethe capacity for self-regulation of the compression at starting.Assuming' that a self-starter or a crank is applied to turn the shaft'D,the pull therefrom 'straightens ,the chain on the right-hand side by theyielding of the spring T, so that while the lever 'P and pulley R remainstationary, the lever arm S and the pulley R yield to the extent of thegap between the screws U U.

U U and spring adjustment T are provided.

main to be described.

For rigidly connecting together the parts of the engine, tie rods 7c 7care provided having nuts at their opposite ends holding in The lowerbase of the engine is shown as a 1 ings.

position the bearings-which support respectively -the crank shaft andvalve shaft.

casting m which forms the crank case and has transverse brackets Zapproaching each other for supporting the crank shaft beartically,forming sockets for the passage of the tie rods k. Beneath the bracketsare received projecting'. ears`- of a bearin block n constituting thelower half of At e crank shaft bearing.

- of this bearing is fastened down by screws o tothe tops of thebrackets Z, and constitutes the rigid member of the bearing. The lower4member 'n is adjustable for wear by removing shims p and substitutingthinner ones. The greater part 0f the wear is a ainst the pass up on thecylinder casting a, and are continued upward above the cylinder castingthrough tubular bearing supports g preferably constructed as a separatemember and integral with the lower members of the bearings for the shaftG.

The power pitman C is shown as connected with the plunger B by apreferably tubular wrist pin c, the pitmanhead being widened on thelower side to give the maximum contact surface for transmission of powerand narrowed on the upper side to give less contact surface for pullingdown. the plunger during the suction stroke; and the plunger having awrist pin housing 1' which is recip- This actioncauses the valve shaftto lag to a corresponding ex- Some desirable details of construction re-These brackets Z are perforated ver-v The upper half n (Fig. l2)

rocally. widened at the lower side and narrowed at the upper side togive it the maximum bearing surface against the pin during the powerstroke. The pin is he d in position longitudinally so that its endscannot come into contact with the cylinder lining, by means of a ring swhich is sprungaround the plunger, entering a groove therein, and whichcrosses the opposite ends-of the pin. This ring s might constitute one0f the packing rings of the plunger.

The pitmen H engage short wrist pins t t, preferably tubular, which-areclamped at their middles with cross bars or bridges u cast as part 0fthe -valve piston E, being held rigidly' downupon these bridgesbyclamping caps o similar to bearing caps. The pitmen H are forked andengage the protruding ends of the pins t. In Fig. l1 the valve piston Eis shown in plan. with the pitmen H in section, that on the left'justbeneath the cap v which is removed, and that on the right just above thecap.4

In Fig. l a spark plug eis shown in place. On thel opposite side of thecylinder a socket e is shown which may receive another spark plug, asshown in dotted lines, or may be. closed by a solid plug. J

For a single-cylinder engine it is desirable k to provide both the crankshaftD and valve shaft G with fly wheels shown at D and G',respectively,.but. for a multi-cylinder engine one or both of these maybe omitted.

It is desirable to case in the engine and for this purpose a casing isshown consisting of side plates 27, 27 (Fig. l), end plates 28,

28 (Fig. 2), and top plates 29, 29 (Figs. 1

vjacket to circulate it through the exhaust jacket g. This flow is showndiagrammatically in Fig. 1 in dotted lines, 30 being the inlet to g', 31the duct leading from the top 0f the latter to thebottom of the cylinderjacket, 32 a duct from the top of said jacket to the bottom of g, and 33the outlet to the radiator.

" The purpose of introducing' the coolest water around .the intakemanifold is to cool the mixture before its admission through the inletports and ,into the annular chamber 19, as this cooling of theintakemixture is .n

relied upon to cool the valves.

the inlet valve of some of the mixture during the return stroke of theplunger drives out someresidue of the heated spent gases lThis is espefcially desirable because the rexpulsion from mixed with the expelledcombustible mixture, and this latter is also heated in circulating intoand out of the cylinder and through the valves, so that it becomesdesirable to cool the gases by the circulation of cool water through theintake jacket.

It is to be understood that the invention is not limited to the detailsof construction ing in said cylinder affording sole control forshown andthat the general arrangement, proportions and engineering design may beconsiderably modified without departing from the invention. A

What I claim is 1 l.v In an engine of the described type having a maincylinder and piston valves within said cylinder affording the solecontrol for the inlet and exhaust, and a valve shaft operativelyconnected to said valves, whereby the piston valves are adapted torecede during the power stroke and thereby communicate power to theValve shaft, said valves cooperating to control the inlet, and one ofsaid valves acting alone to control the exhaust.

2. In an engine of the described type hava main cylinder and pistonvalves withthe inlet and exhaust, and a valve shaft to which said valvesare connected, a piston and crank shaft to which said valve shaft isconnected said piston valves and shaft bein related to cause the pistonvalves to rece e during the power stroke, and thereby to communicatepower to the valve shaft, said valves cooperating and one of said valvesacting alone to control the. exhaust.v

3. In an engine of the described type hav,- ing piston valves affordingsole control for the inlet and exhaust, valve actuating cranks to whichsaid valves are connected, a piston andv power shaft, and a connectionbetween said' power shafts and valve actuating cranks whereby the pistonvalves have continuous uninterrupted movement coinciding with the crankthrow, and said valves to control the inlet, v

co'perating to control the inlet, and one of said valves acting alone tocontrol the exhaust.

4. ln an engine of the character described, the combination of acylinder .having inlet and exhaust ports, piston valves within thecylinder which afford the sole control for the inlet and exhaust, avalve shaft opera'- tively connected to said valves, a piston and crankshaft to which said valve shaft is operatively connected, the saidvalves being relatively movable and constructed and arranged wherebythey coperate to control the inlet, and whereby one of said valves actsalone to control the exhaust. v

5. ln an engine of-the character described, the combination of acylinder having inlet and exhaust ports, valve mechanism within thecylinder aordingA the sole control for the inlet and exhaust, said Valvemechanism including relatively movable concentrically arrangedcylindrical pistons, an actuating shaft for said pistons, and saidpistons being constructed and arranged whereby in the action'of saidshaft they coperate to control the inlet, and whereby one of saidpistons acts alone to control the exhaust.

6. In an engine of the character described, a cylinder having separateinlet and exhaust ports, the combination of piston valve membersarranged one within the other in said cylinder and affording the solecontrol for the inlet andexhau'st, a shaft for said members, a pistonand crank shaft, said crank shaft having connection with the valve shaftwhereby said valves are posiantan w. HALL.

